In general, in a plasma display panel (PDP), discharge gas is filled in spaces between opposing glass substrates. In this structure, discharges are generated by electrodes disposed in a matrix form, and phosphors of the cells separated by barrier ribs are excited by the discharges to emit light. A drive circuit which applies voltages to each electrode is disposed on a rear side of the PDP, and the PDP is electrically connected to the drive circuit via a flexible substrate. An example of this structure is disclosed in the technology of Japanese Patent Application Laid-Open Publication No. 2003-216054 (Patent Document 1).
The flexible substrate is usually disposed on a metal plate, and an edge portion of the metal plate is coated with resin such as silicon for the purpose of improving moisture resistance. An example of this structure is disclosed in the technology of Japanese Patent Application Laid-Open Publication No. 2005-38636 (Patent Document 2).
FIG. 9 to FIG. 11 are explanatory drawings showing a structure example of a conventional PDP module for comparison with an embodiment of the present invention. FIG. 9 is a detail drawing showing a structure example of a conventional driver module (40). The conventional driver module (40) includes a metal plate 21 serving as a heat radiating member, a flexible substrate 28 having wiring patterns connected to electrodes of a panel, and others.
In the conventional module (40), the flexible substrate 28 is attached to the metal plate 21, and further a driver IC 25 is mounted. The wirings on the flexible substrate 28 include ground lines 24 connected to the ground of the driver module (40) and signal wirings 23 connected to each address electrode 15, which are disposed on the outermost sides of the flexible substrate 28. Although it depends on the type of the driver IC 25, the number of the signal wirings 23 may be 64, 128, or others. Meanwhile, holes 29 which are used for mounting on mounting parts (3a) of a chassis (3) are formed in the metal plate 21. Further, although one driver IC 25 is mounted on one metal plate 21 in this example, a plurality of driver ICs are mounted in some cases. When three driver ICs with 128 lines are mounted, 384 address electrodes can be driven by one driver module, and when eight driver modules are provided, 3072 address electrodes can be driven. Since one pixel consists of three colors of RGB, the number of pixels in the lateral direction is 1024 in this case. Also in this case, the ground lines 24 are disposed on both outer sides of the flexible substrate 28 in each driver module (40).
FIG. 10 is a partially enlarged view showing the wirings near the boundary between the flexible substrate 28 and the metal plate 21 in the conventional driver module (40) shown in FIG. 9. On the flexible substrate 28, the wirings (23 and 24) to the electrodes of the panel are disposed near the edges in the width direction of the flexible substrate 28.
FIG. 11 is a diagram showing the case where the conventional driver modules 40 are connected to the rear substrate 2. The ground lines 24a and 24b are connected to longitudinal lines on both outer sides of a display area of the PDP, and the signal wirings 23 are connected to the address electrodes. On the other hand, other ground lines 24 are not connected to the electrodes of the rear substrate 2.